Men with positive family histories of alcoholism constitute one group at high risk (HR) for developing alcoholism. The proposed research assesses the general hypotheses that psychological and physiological characteristics distinguish HR and control subjects while sober, and also after acute alcohol administration. Healthy, 18 to 26 year old, non-problem drinking caucasian males will serve as subjects. The HR group will be defined as men with at least one male biological relative evidencing symptoms indicative of alcoholism; matched controls will consist of men without family histories of alcoholism or other psychiatric disorder. All subjects will undergo a two phase screening process, with final selection based upon the results of structured DSM-III-R criteria. Using multiple measures in a double-blind, placebo-controlled experiment, each subject will undergo evaluation in four experimental sessions, during which either alcohol (0.5, 0.75, 1.0 ml/kg) or placebo is orally administered. Physiological and psychological measures are acquired prior to, and at multiple temporal points following beverage administrations. The design thus provides a basis for verifying that HR and control group differences are specifically attributable to alcohol, and for assessing specific dose effects. Physiological measures will consist of indices derived from the electroencephalogram; the auditory event related potential (elicited by an oddball paradigm, to permit P3 assessment); the pattern reversal visual evoked potential; serum prolactin; serum cortisol; and, breath alcohol level. Psychological measures will consist of subjective reports of intoxication, anxiety and somatic symptoms; observer-ratings of subjects; and, reaction time and visuomotor performance. Potential mediators of HR and control group differences elicited by alcohol administration can be evaluated on the basis of placebo session data, and on the basis of additional measures obtained while they are sober (personality; beliefs and expectations of alcohol effects; platelet monoamine oxidase activity). In summary, this is the first dose response study of alcohol effects in men at high risk for alcoholism to include such a broad array of physiological and psychological measures in a double blind, placebo-controlled, within- subject design. The design, by providing a basis for evaluating interaction between subject risk status, alcohol dosage, physiological markers, and psychological factors will contribute to knowledge about processes relevant to alcoholism and etiological theories concerning its development.